Spatial input apparatus

Abstract

A three-dimensional spatial input apparatus including a series of coplanar, single axis accelerometers configured to provide information on translation along and rotation around a set of orthogonal axes. A preprocessing computer determines the acceleration values output by the accelerometers and converts these values into a series of acceleration, velocity and position values in relation to the axis system, with corrections based on a change in the influence of gravity on the device as it rotates. The values are transmitted to an object control computer which takes appropriate action, including moving a cursor, rotating a displayed object, and controlling remote devices. The spatial input apparatus can have an attached pointer and be used as a three-dimensional digitizer in conjunction with the object control computer.

We claim: 
     
       1. An apparatus for providing spatial orientation data signals, comprising: an inertial platform accelerometer cluster having three orthogonal axes and a plurality of accelerometers arranged to provide signals indicative of linear acceleration of said platform along each of the three axes and rotational acceleration of said platform about each of the three axes, said accelerometers all having their centers of measurement coplanar;   processing means for receiving said accelerometer signals and providing output signals representative of linear acceleration along each of the three axes and rotational acceleration about each of the three axes.   
     
     
       2. The apparatus of claim 1, wherein said processing means further provides output signals indicative of the linear and rotational velocities relative to each of the three axes, and the instantaneous linear and rotational positions of the apparatus.   
     
     
       3. The apparatus of claim 1, further comprising: housing means for containing said accelerometer cluster; and   switch means operated by the user to provide a switch closure signal to said processing means.   
     
     
       4. The apparatus of claim 3, further comprising: pointer means for tracing the shape of an object, said pointer means having a tip for contacting the contour of the object to be digitized, said pointer tip being mounted with said housing means in a defined spatial relationship thereto to provide a means for indicating a point remote from said cluster center.   
     
     
       5. The apparatus of claim 1, further comprising: resting switch means for providing a signal indicative of when said accelerometer cluster is resting on a surface.   
     
     
       6. A system for controlling the movement of an object in response to directional control signals, comprising: an inertial platform means for manipulation by the user to indicate the desired movement of the object, said inertial platform means including a plurality of accelerometers for sensing movements o the platform by the user along each of three orthogonal axes and means for providing directional control signals indicative of the linear accelerations along each of the three axes and the rotational accelerations about each of the three axes;   means for receiving said directional control signals;   means for controlling the movement of the object responsive to said directional control signals thereby causing the object to mimic the movement of said inertial platform.   
     
     
       7. The object control system of claim 6, wherein the object is a cursor represented on a graphic display device and said control means includes means for controlling movement of a cursor on a graphic display device. 
     
     
       8. The object control system of claim 6, wherein the object is a representation of a physical object on a graphic display device and said control means includes means for controlling the movement of a physical object displayed on a graphic display device. 
     
     
       9. The object control system of claim 6, wherein the object is a remote manipulator, and said control means includes means for controlling the movement of a remote manipulator. 
     
     
       10. The object control system of claim 6, further comprising: housing means for containing said inertial platform means; and   switch means operated by the user to provide a switch closure signal to said control means.   
     
     
       11. The object control system of claim 6, wherein said control means includes means for limiting the movement of the object to translation along each of two axes and rotation about the third axis. 
     
     
       12. A system for digitizing a three-dimensional surface, comprising: an inertial platform means for manipulation by the user to indicate the desired position to be digitized, said inertial platform means includes a plurality of accelerometers for sensing movements of the platform by the user along each of three orthogonal axes and means for providing directional signals indicative of the linear accelerations along each of the three axes and the rotational accelerations about each of the three axes;   processing means for receiving said directional signals and providing signals indicative of the linear and rotational position of said inertial platform means; and   means for storing a plurality of said linear position signals and for developing a three dimensional representation of the stored positions.   
     
     
       13. The digitizing system of claim 12, further comprising: housing means for containing said inertial platform means;   switch means operated by the user to provide a switch closure signal to said control means to indicate selection of position signals to be stored by said storage means.   
     
     
       14. The digitizing system of claim 13, further comprising: pointer means for tracing the shape of an object, said pointer means having a tip for contacting the contour of the object to be digitized, said pointer tip being mounted with said housing means in a defined spatial relationship thereto to provide a means for indicating a point remote from said inertial platform means center; and   interpretation means for translating said inertial platform means position location and rotation signals to indicate the position of said pointer tip for storage by said storage means.   
     
     
       15. The digitizing system of claim 14, further comprising: means for determining the location of said pointer tip with relation to said inertial platform means.   
     
     
       16. The digitizing system of claim 13, further comprising: crosshair means for digitizing a two dimensional surface, said crosshair means being mounted with said housing means in a defined spatial relationship to provide a means for indicating a point remote from said inertial platform means center when said inertial platform means is resting on a flat surface.